Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

When comparing large targets like //chrome, it is nearly impossible to deal with
the mountainous 46,000 lines of output the executable script produces. With an
interactive environment, it is much easier to compare differences and drill-down
into specific issues.

BUG=622889
R=scottmg@chromium.org

Committed: https://chromium.googlesource.com/chromium/src/+/9f1375ea1bfb9f35e48b69f4c10c8ffa3233ca2a

[scottmg, 2016-06-28 18:47:54]

lgtm

[commit-bot: I haz the power, 2016-06-28 19:29:28]

Description was changed from

==========
Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

When comparing large targets like //chrome, it is nearly impossible to deal with
the mountainous 46,000 lines of output the executable script produces. With an
interactive environment, it is much easier to compare differences and drill-down
into specific issues.

BUG=622889
R=scottmg@chromium.org
==========

to

==========
Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

When comparing large targets like //chrome, it is nearly impossible to deal with
the mountainous 46,000 lines of output the executable script produces. With an
interactive environment, it is much easier to compare differences and drill-down
into specific issues.

BUG=622889
R=scottmg@chromium.org

Committed: https://crrev.com/9f1375ea1bfb9f35e48b69f4c10c8ffa3233ca2a
Cr-Commit-Position: refs/heads/master@{#402512}
==========

[commit-bot: I haz the power, 2016-06-28 19:29:29]

Patchset 1 (id:??) landed as
https://crrev.com/9f1375ea1bfb9f35e48b69f4c10c8ffa3233ca2a
Cr-Commit-Position: refs/heads/master@{#402512}

[Robert Sesek, 2016-06-28 19:30:34]

Description was changed from

==========
Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

When comparing large targets like //chrome, it is nearly impossible to deal with
the mountainous 46,000 lines of output the executable script produces. With an
interactive environment, it is much easier to compare differences and drill-down
into specific issues.

BUG=622889
R=scottmg@chromium.org

Committed: https://crrev.com/9f1375ea1bfb9f35e48b69f4c10c8ffa3233ca2a
Cr-Commit-Position: refs/heads/master@{#402512}
==========

to

==========
Refactor //tools/gn/bin/gyp_flag_compare.py to be usable in interactive Python.

When comparing large targets like //chrome, it is nearly impossible to deal with
the mountainous 46,000 lines of output the executable script produces. With an
interactive environment, it is much easier to compare differences and drill-down
into specific issues.

BUG=622889
R=scottmg@chromium.org

Committed:
https://chromium.googlesource.com/chromium/src/+/9f1375ea1bfb9f35e48b69f4c10c...
==========

[Robert Sesek, 2016-06-28 19:30:35]

Committed patchset #1 (id:1) manually as
9f1375ea1bfb9f35e48b69f4c10c8ffa3233ca2a (presubmit successful).

[Khushal, 2016-06-28 19:53:20]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2104083002/ by khushalsagar@chromium.org.

The reason for reverting is: A significant number of bots are broken after this
landed. This is a speculative revert. Please re-land in case this was not the
error..